Collagen degrading activity associated withMycobacterium species
- aDepartamento de Biología Celular, Instituto Nacional de Cardiología “Ignacio Chávez”, Juan Badiano 1, Tlalpan 14080, Mexico, bDepartamento de Biología Desarrollo, Instituto de Investigaciones Biomédicas, UNAM, Mexico, cDepartamento de Bioquímica, Instituto Nacional Enfermedades Respiratorias, Tlalpan, México
- Dr L F Montaño.
- Received 13 August 1998
- Revision requested 28 September 1998
- Revised 20 November 1998
- Accepted 5 January 1999
Abstract
BACKGROUND The mechanism of Mycobacterium tuberculosispenetration into tissues is poorly understood but it is reasonable to assume that there is a contribution from proteases capable of disrupting the extracellular matrix of the pulmonary epithelium and the blood vessels. A study was undertaken to identify and characterise collagen degrading activity of M tuberculosis.
METHODS Culture filtrate protein extract (CFPE) was obtained from reference mycobacterial strains and mycobacteria isolated from patients with tuberculosis. The collagen degrading activity of CFPE was determined according to the method of Johnson-Wint using 3H-type I collagen. The enzyme was identified by the Birkedal-Hansen and Taylor method and its molecular mass determined by SDS-PAGE and Sephacryl S-300 gel filtration chromatography using an electroelution purified enzyme.
RESULTS CFPE fromMycobacterium tuberculosis strain H37Rv showed collagenolytic activity that was four times higher than that of the avirulent strain H37Ra. The 75 kDa enzyme responsible was divalent cation dependent. Other mycobacterial species and those isolated from patients with tuberculosis also had collagen degrading activity.
CONCLUSIONS Mycobacteriumspecies possess a metalloprotease with collagen degrading activity. The highest enzymatic activity was found in the virulent reference strain H37Rv.
